FIG. 1 illustrates a section of a related art washing machine. As shown, the washing machine is provided with a cabinet 11 of an exterior of the washing machine, a tub 21 in the cabinet 11 for holding washing water, and a drum 31 rotatably mounted in the tub 21. There are suspension springs 23 and dampers 25 over and under the tub 21 for suspending the tub 21.
Above the tub 21, there is a detergent supply unit 27 for supplying detergent, and on one side of the tub 21, there is a water supply pipe 35 having a water supply valve 37 mounted thereon. Secured to a rear of the tub 21, there is a drum driving motor 29 for rotating the drum 31. Under the tub 21, there are a drain line 32 and a drain pump 34 for draining, and on a bottom of the tub 21, there are a heater room 24 and a heater 26 for heating washing water held therein.
In the meantime, there are a plurality of lifters 33 on an inside of the drum 31 each projected in a radial direction and extended in an axis direction for lifting and dropping the laundry.
According to above configuration, once the laundry is introduced into the drum 31 and a washing cycle is started, the water supply valve 37 is opened, and the detergent and the washing water is supplied to the tub 21. In this instance, as the drum 31 rotates in regular/reverse directions, the laundry wet with water, to drop a water level of the washing water in the tub 21. For making up the drop of the water level, washing water is supplied, additionally.
If the drum 31 rotates, a washing action is made as the laundry in the drum 31 is lifted up and dropped down. The heater 26 heats the washing water to a preset temperature according to user's selection, to improve a washing performance.
Once the washing is finished, the drain pump 34 is driven, to make drain, and the drum 31 is rotated, to make so called intermittent spinning for smooth draining of the washing water from the laundry.
Upon finishing the draining, while rotating the drum 31, water is supplied to the tub 21, to perform rinsing. After repeating the rinsing and the intermittent spinning a few times, spinning is performed finally, to finish the washing.
However, the related art method for washing laundry by a washing machine has problems in that the heater room 24 recessed down in a bottom of the tub 21 and heater 26 arranged therein for heating the washing water held in the heater room 24 makes the washing and rinsing poor due to detergent remained in the heater room 24, and increases consumption of the washing water and power due to an amount of washing water required to fill the heater room 24, additionally.